Author: Jonathan Losos Page 57 of 130

A few months back, we had a post on the conservation situation in Jamaica with particular emphasis on the Hellshire Hills, last redoubt of the Jamaican iguana. Now in the journal Oryx, Rick Van Veen and Byron Wilson of the University of the West Indies, along with Tandora Grant and Richard Hudson, of the San Diego and Fort Worth Zoos, respectively, express further concern of the situation. Most of the article can be viewed online; add “and the environmental conventions to which it is a signatory.” to the last line and you’ve got the whole article.

Let’s face it, “squamate” doesn’t work. It’s an ugly word, and most people don’t know what it means–if anything, it conjures up “squamous cell carcinoma,” a type of skin cancer.

More importantly, the term is not needed. Squamate comes from the scientific order Squamata, the lizards and snakes. But we know that snakes evolved from lizards–they are one type of lizard. In other words, lizards do not form a monophyletic group; they are paraphyletic with respect to snakes.

Does this remind you of any other major group of vertebrate? Say, birds and dinosaurs? We all know that birds evolved from dinosaurs, they are a type of dinosaur; dinosaurs are paraphyletic with respect to birds. And so, what is the solution to this problem? We now realize that birds are dinosaurs, members of the Dinosauria. Indeed, failing to recognize birds as a type of dinosaur commits the sin of paraphyly, obscuring the fact that some dinosaurs (in the old sense) are more closely related to birds than they are to some other dinosaurs.

And so, for the same reason, we should start referring to snakes as one type of lizards and, in turn, when we use the term “lizard,” we should understand that we are referring to snakes as well. In other words “Lizard” = Squamata. And, hence, we have no need to use the term “squamate” in common discourse.

Ahh, that warmth feels good.

We all know that many anoles species are very good at behaviorally regulating their body temperature by moving from an area that is too hot or too cold to another area that is just right. But how do they actually judge the thermal properties of a particular microsite? There’s been a lot of work on the sensation of temperature in mammals, but not so much in reptiles.

Recently, Erkin Kurganov and colleagues at the National Institutes of Natural Sciences, in Okazaki, Japan began to rectify this shortcoming, and their paper has just been published in Pflügers Archiv – European Journal of Physiology. Here’s the abstract: 

Transient receptor potential ankyrin 1 (TRPA1) is a member of the large TRP super family of ion channels and functions as a Ca2+-permeable nonselective cation channel that is activated by various noxious stimuli. TRPA1 was initially identified as a potential mediator of noxious cold stimuli in mammalian nociceptive sensory neurons, while TRPA1s from nonmammalian vertebrates (snakes, green anole lizards, and frogs) were recently reported to be activated by heat, but not cold stimulus. In this study, we examined detailed properties of the green anole TRPA1 channel (gaTRPA1) related to thermal and chemical stimulation in whole-cell and single-channel recordings. Heat activates gaTRPA1 with a temperature threshold for activation of 35.8 °C, while heat together with allyl isothiocyanate (AITC), a chemical agonist, had synergistic effects on gaTRPA1 channel activation in that either the temperature threshold or activating AITC concentration was reduced in the presence of the other stimulus. Significant heat-evoked gaTRPA1 activation was observed in the presence but not absence of extracellular Ca2+. gaTRPA1 channels were also activated by heat and AITC in excised membrane patches with an inside-out configuration. By comparing the kinetics of heat- and AITC-evoked singlechannel currents, we defined similarities and differences of gaTRPA1 channel responses to heat and AITC. We observed similar current-voltage relationship and unitary amplitudes for heat- and AITC-evoked currents and found that heat-activated currents showed shorter durations of both open and closed times. Our results suggest that the gaTRPA1 channel is directly activated by heat and chemical stimuli.

Ron Savage, who works for USAID and is currently posted in Haiti, reports “I haven’t been getting out herping in Haiti much since I sold my car but today I managed to go out and check out some relictual forest (at about 2,700 ft elev.) not too far from Port au Prince and photographed these two anoles. This is the first time that I’ve seen this species in Haiti or the DR come to think of it. They were both up a tree about 15-20 feet and I would say that they were both about 8-9” long including their tails. As you can see, one has a stump tail. He was higher in the tree keeping his eye on the greener one. I honestly don’t know what these are, do you have any idea? It could actually be two species. I’m not familiar with A. ricordii, but I suppose this could be one.”

Reports Pat Shipman in Little Cayman, adding “Notice the difference between her expression and his.  Anolis maynardi on Little Cayman, just after a nice rain.”

And notice that sexual dimorphism in snout length!

Photo by Jake Scott

Some people think so, such as this posting on the Association of South Eastern Herpetogists website. I have my doubts about the presence of porcatus in Florida. Anolis carolinensis, after all, is derived from A. porcatus. In reality, it is simply a population of A. porcatus, perhaps smaller than most of their Cuban comrades. Suppose for some reason A. carolinensis started growing larger–wouldn’t they look like the green anoles on Cuba? Anyone have thoughts on whether Cuban porcatus are really in Florida and, if so, how easy it is to identify them?

Photo by Christopher Kirby

Here’s another putative porcatus, this one photographed by Christopher Kirby. Those heads are pretty mean looking, I’ll grant that. Several other photos are also on the ASEH website.

Check out this green anole photographed at the Archbold Biological Station in Florida by Nick Fletcher, participating in a Cornell University field trip led by Harry Greene.

Green anole. Photo by Nick Fletcher.

Photo by Nick Fletcher.

And here’s one more by Nick, taken a day later.

Photo by Nick Fletcher.

From the pages of Sports Illustrated, 25 years ago today

That’s my thumb! Ain’t she a beauty?

A few months ago, I ran into Nicholas Dawidoff, the author of the fabulous new book Collision Low Crossers: A Year Inside the Turbulent World of NFL Football. Seeing Nicholas reminded me of the article he wrote for Sports Illustrated at the very dawn of his writing career, 25 years ago today. The article was on the then developing field of performance studies, measuring the sprinting, jumping, clinging and other capabilities of small ectotherms, and featuring none other than yours truly, as well as Ray Huey, Al Bennett, and Sharon Emerson. Written tongue-in-cheek, but accurately and respectfully, the article was a very nice overview of that emerging field of study. It’s worth checking out the article just to see the wacky pictures taken by the SI photographer sent out on assignment to Seattle and Berkeley.

Inexplicably, the article didn’t make the cover

Blurb: “This guide will allow nearly everyone with an interest in amphibians and reptiles to collect and store samples for genetic analyses. It is written at a level appropriate for people with a basic background in biology, including professional scientists moving into a new project as well as wildlife managers, conservation biologists, ecologists, and others working on herpetological projects. The book should also be useful for advanced undergraduates and graduate students just starting their research careers.”

See more at the SSAR book website.

Price: $11